- December 16th, 2014 1174
The “Callback Secret” parameter is used to prevent bogus or fake callbacks to your payment gateway callback handler. The parameter should not be given to anyone as this is a “secret”. The value of this parameter can be anything you want, any alpha-numeric characters you’d like of any length (though we recommend 12 – 24 characters or so).
We’ve even generated one for you (unique to your browser request). You can copy / paste this into the Callback Secret parameter field.